/*
 * Copyright (C) 2008 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.emay.sdk.util.json.gson;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * A class representing an array type in Json. An array is a list of
 * {@link JsonElement}s each of which can be of a different type. This is an
 * ordered list, meaning that the order in which elements are added is
 * preserved.
 *
 * @author Inderjeet Singh
 * @author Joel Leitch
 */
public final class JsonArray extends JsonElement implements Iterable<JsonElement> {
	private final List<JsonElement> elements;

	/**
	 * Creates an empty JsonArray.
	 */
	public JsonArray() {
		elements = new ArrayList<JsonElement>();
	}

	@Override
	JsonArray deepCopy() {
		JsonArray result = new JsonArray();
		for (JsonElement element : elements) {
			result.add(element.deepCopy());
		}
		return result;
	}

	/**
	 * Adds the specified boolean to self.
	 *
	 * @param bool
	 *            the boolean that needs to be added to the array.
	 */
	public void add(Boolean bool) {
		elements.add(bool == null ? JsonNull.INSTANCE : new JsonPrimitive(bool));
	}

	/**
	 * Adds the specified character to self.
	 *
	 * @param character
	 *            the character that needs to be added to the array.
	 */
	public void add(Character character) {
		elements.add(character == null ? JsonNull.INSTANCE : new JsonPrimitive(character));
	}

	/**
	 * Adds the specified number to self.
	 *
	 * @param number
	 *            the number that needs to be added to the array.
	 */
	public void add(Number number) {
		elements.add(number == null ? JsonNull.INSTANCE : new JsonPrimitive(number));
	}

	/**
	 * Adds the specified string to self.
	 *
	 * @param string
	 *            the string that needs to be added to the array.
	 */
	public void add(String string) {
		elements.add(string == null ? JsonNull.INSTANCE : new JsonPrimitive(string));
	}

	/**
	 * Adds the specified element to self.
	 *
	 * @param element
	 *            the element that needs to be added to the array.
	 */
	public void add(JsonElement element) {
		if (element == null) {
			element = JsonNull.INSTANCE;
		}
		elements.add(element);
	}

	/**
	 * Adds all the elements of the specified array to self.
	 *
	 * @param array
	 *            the array whose elements need to be added to the array.
	 */
	public void addAll(JsonArray array) {
		elements.addAll(array.elements);
	}

	/**
	 * Replaces the element at the specified position in this array with the
	 * specified element. Element can be null.
	 * 
	 * @param index
	 *            index of the element to replace
	 * @param element
	 *            element to be stored at the specified position
	 * @return the element previously at the specified position
	 * @throws IndexOutOfBoundsException
	 *             if the specified index is outside the array bounds
	 */
	public JsonElement set(int index, JsonElement element) {
		return elements.set(index, element);
	}

	/**
	 * Removes the first occurrence of the specified element from this array, if it
	 * is present. If the array does not contain the element, it is unchanged.
	 * 
	 * @param element
	 *            element to be removed from this array, if present
	 * @return true if this array contained the specified element, false otherwise
	 * @since 2.3
	 */
	public boolean remove(JsonElement element) {
		return elements.remove(element);
	}

	/**
	 * Removes the element at the specified position in this array. Shifts any
	 * subsequent elements to the left (subtracts one from their indices). Returns
	 * the element that was removed from the array.
	 * 
	 * @param index
	 *            index the index of the element to be removed
	 * @return the element previously at the specified position
	 * @throws IndexOutOfBoundsException
	 *             if the specified index is outside the array bounds
	 * @since 2.3
	 */
	public JsonElement remove(int index) {
		return elements.remove(index);
	}

	/**
	 * Returns true if this array contains the specified element.
	 * 
	 * @return true if this array contains the specified element.
	 * @param element
	 *            whose presence in this array is to be tested
	 * @since 2.3
	 */
	public boolean contains(JsonElement element) {
		return elements.contains(element);
	}

	/**
	 * Returns the number of elements in the array.
	 *
	 * @return the number of elements in the array.
	 */
	public int size() {
		return elements.size();
	}

	/**
	 * Returns an iterator to navigate the elements of the array. Since the array is
	 * an ordered list, the iterator navigates the elements in the order they were
	 * inserted.
	 *
	 * @return an iterator to navigate the elements of the array.
	 */
	public Iterator<JsonElement> iterator() {
		return elements.iterator();
	}

	/**
	 * Returns the ith element of the array.
	 *
	 * @param i
	 *            the index of the element that is being sought.
	 * @return the element present at the ith index.
	 * @throws IndexOutOfBoundsException
	 *             if i is negative or greater than or equal to the {@link #size()}
	 *             of the array.
	 */
	public JsonElement get(int i) {
		return elements.get(i);
	}

	/**
	 * convenience method to get this array as a {@link Number} if it contains a
	 * single element.
	 *
	 * @return get this element as a number if it is single element array.
	 * @throws ClassCastException
	 *             if the element in the array is of not a {@link JsonPrimitive} and
	 *             is not a valid Number.
	 * @throws IllegalStateException
	 *             if the array has more than one element.
	 */
	@Override
	public Number getAsNumber() {
		if (elements.size() == 1) {
			return elements.get(0).getAsNumber();
		}
		throw new IllegalStateException();
	}

	/**
	 * convenience method to get this array as a {@link String} if it contains a
	 * single element.
	 *
	 * @return get this element as a String if it is single element array.
	 * @throws ClassCastException
	 *             if the element in the array is of not a {@link JsonPrimitive} and
	 *             is not a valid String.
	 * @throws IllegalStateException
	 *             if the array has more than one element.
	 */
	@Override
	public String getAsString() {
		if (elements.size() == 1) {
			return elements.get(0).getAsString();
		}
		throw new IllegalStateException();
	}

	/**
	 * convenience method to get this array as a double if it contains a single
	 * element.
	 *
	 * @return get this element as a double if it is single element array.
	 * @throws ClassCastException
	 *             if the element in the array is of not a {@link JsonPrimitive} and
	 *             is not a valid double.
	 * @throws IllegalStateException
	 *             if the array has more than one element.
	 */
	@Override
	public double getAsDouble() {
		if (elements.size() == 1) {
			return elements.get(0).getAsDouble();
		}
		throw new IllegalStateException();
	}

	/**
	 * convenience method to get this array as a {@link BigDecimal} if it contains a
	 * single element.
	 *
	 * @return get this element as a {@link BigDecimal} if it is single element
	 *         array.
	 * @throws ClassCastException
	 *             if the element in the array is of not a {@link JsonPrimitive}.
	 * @throws NumberFormatException
	 *             if the element at index 0 is not a valid {@link BigDecimal}.
	 * @throws IllegalStateException
	 *             if the array has more than one element.
	 * @since 1.2
	 */
	@Override
	public BigDecimal getAsBigDecimal() {
		if (elements.size() == 1) {
			return elements.get(0).getAsBigDecimal();
		}
		throw new IllegalStateException();
	}

	/**
	 * convenience method to get this array as a {@link BigInteger} if it contains a
	 * single element.
	 *
	 * @return get this element as a {@link BigInteger} if it is single element
	 *         array.
	 * @throws ClassCastException
	 *             if the element in the array is of not a {@link JsonPrimitive}.
	 * @throws NumberFormatException
	 *             if the element at index 0 is not a valid {@link BigInteger}.
	 * @throws IllegalStateException
	 *             if the array has more than one element.
	 * @since 1.2
	 */
	@Override
	public BigInteger getAsBigInteger() {
		if (elements.size() == 1) {
			return elements.get(0).getAsBigInteger();
		}
		throw new IllegalStateException();
	}

	/**
	 * convenience method to get this array as a float if it contains a single
	 * element.
	 *
	 * @return get this element as a float if it is single element array.
	 * @throws ClassCastException
	 *             if the element in the array is of not a {@link JsonPrimitive} and
	 *             is not a valid float.
	 * @throws IllegalStateException
	 *             if the array has more than one element.
	 */
	@Override
	public float getAsFloat() {
		if (elements.size() == 1) {
			return elements.get(0).getAsFloat();
		}
		throw new IllegalStateException();
	}

	/**
	 * convenience method to get this array as a long if it contains a single
	 * element.
	 *
	 * @return get this element as a long if it is single element array.
	 * @throws ClassCastException
	 *             if the element in the array is of not a {@link JsonPrimitive} and
	 *             is not a valid long.
	 * @throws IllegalStateException
	 *             if the array has more than one element.
	 */
	@Override
	public long getAsLong() {
		if (elements.size() == 1) {
			return elements.get(0).getAsLong();
		}
		throw new IllegalStateException();
	}

	/**
	 * convenience method to get this array as an integer if it contains a single
	 * element.
	 *
	 * @return get this element as an integer if it is single element array.
	 * @throws ClassCastException
	 *             if the element in the array is of not a {@link JsonPrimitive} and
	 *             is not a valid integer.
	 * @throws IllegalStateException
	 *             if the array has more than one element.
	 */
	@Override
	public int getAsInt() {
		if (elements.size() == 1) {
			return elements.get(0).getAsInt();
		}
		throw new IllegalStateException();
	}

	@Override
	public byte getAsByte() {
		if (elements.size() == 1) {
			return elements.get(0).getAsByte();
		}
		throw new IllegalStateException();
	}

	@Override
	public char getAsCharacter() {
		if (elements.size() == 1) {
			return elements.get(0).getAsCharacter();
		}
		throw new IllegalStateException();
	}

	/**
	 * convenience method to get this array as a primitive short if it contains a
	 * single element.
	 *
	 * @return get this element as a primitive short if it is single element array.
	 * @throws ClassCastException
	 *             if the element in the array is of not a {@link JsonPrimitive} and
	 *             is not a valid short.
	 * @throws IllegalStateException
	 *             if the array has more than one element.
	 */
	@Override
	public short getAsShort() {
		if (elements.size() == 1) {
			return elements.get(0).getAsShort();
		}
		throw new IllegalStateException();
	}

	/**
	 * convenience method to get this array as a boolean if it contains a single
	 * element.
	 *
	 * @return get this element as a boolean if it is single element array.
	 * @throws ClassCastException
	 *             if the element in the array is of not a {@link JsonPrimitive} and
	 *             is not a valid boolean.
	 * @throws IllegalStateException
	 *             if the array has more than one element.
	 */
	@Override
	public boolean getAsBoolean() {
		if (elements.size() == 1) {
			return elements.get(0).getAsBoolean();
		}
		throw new IllegalStateException();
	}

	@Override
	public boolean equals(Object o) {
		return (o == this) || (o instanceof JsonArray && ((JsonArray) o).elements.equals(elements));
	}

	@Override
	public int hashCode() {
		return elements.hashCode();
	}
}
